Investigators believe parts of a private jet that crashed in Florida and killed all nine onboard may have broken off while it was in the air.

The Learjet 60 had been bound for the Bahamas from Austin, Texas when it nosedived into a multi-lane highway and exploded on impact.

A tech entrepreneur and his young family, as well as the 20-year-old co-pilot, were among those who died on Sunday.

The US National Transportation Safety Board (NTSB) said weather conditions would be a major focus of the investigation but that it was struggling to access the wreckage due to the huge crater created by the jet on the road in Palm Beach.

The plane crashed on Military Trail, a six-lane road that features businesses and restaurants, at around 12:50 local time (17:50 GMT).

“The biggest obstacle that we’re going to have is recovering the major wreckage from the impacted crater on the roadway,” lead investigator Tim Monville said at a news conference on Monday.

The NTSB said the crater, near the entrance to a mobile home park, had become partially filled with water because of severe storms. Heavy rainfall and thunderstorms had been reported in the area at the time of the crash.

Debris was scattered across sports fields, businesses and homes in the area.

“We do have some evidence that there was some breakup of the aircraft before impact,” the NTSB’s Tom Chapman said.

“We may find parts of the aircraft some distance away from the actual impact site.”

Officials are also trying to find out whether a cockpit voice recorder was onboard at the time of the crash and whether it can be recovered.

Flight analysis indicates that the jet was plummeting hundreds of feet per second before it crashed.

In air traffic control audio recordings, someone in the cockpit can be heard reporting “moderate turbulence” and that the crew was “managing the ice”.

They can then be heard saying the plane was “picking up precipitation” and “we need to climb”. Moments later, the same voice said the plane was descending at a rate of 10,000ft (3,048m) per minute.

An emergency was declared and they can be heard yelling “we are in an overspeed condition descending 20,000ft per minute”, before saying, “we are going to crash into the ground”.

Seven passengers died on board, named in a joint statement as tech entrepreneur Adam Robinson, his wife Helen Sharp, and their two children – Emma, four, and Charlie, two – as well as friends of the family Rachael Reed and Charmi Fehr, and nanny Anita Maria Cetina.

The pilot was named in media reports as 55-year-old Jeffrey Gregory, while Nathalia Filgueiras, 20, who earned her pilot’s licence when she was 17, was reported to be the co-pilot.

One man in a car on the ground sustained a leg injury.

Robinson and Sharp’s family described them as “devoted parents” and said their children were “the light of their lives”.

“Helen and Adam were the love affair that will last forever. Their warmth, generosity and gift for making people feel welcome touched so many lives,” the statement read.

Robinson described himself on his LinkedIn page as the founder and CEO of RB2B and Retention.com, and the CEO of Moltsets – all technology companies. Helen Sharp was an artist, according to media reports.

Robinson previously worked at the global financial services business Lehman Brothers and the banking group Barclays. The BBC has contacted the companies.

The joint statement also named nanny Anita Maria Cetina and said she “cared for Emma and Charlie with tenderness and devotion, and she was truly part of the family”.

It added: “She showed us a legacy of unconditional love and devotion.”

Rachel Reed and Charmi Fehr were described in the joint family statement as “full of joy and adventure”.

“They loved their people fiercely, fully and without hesitation. From the moment they met, they were all in on each other and the life they were building.”

Nathalia Filgueiras’s mother, Camila Corteleti, confirmed to US media that her daughter had died in the crash.

Corteleti told the New York Times: “She loved the freedom. It was completely different seeing the world from the top.”

Filgueiras had spoken of her pride at receiving her pilot’s licence while still a senior in high school in an interview with a local affiliate of CBS News in 2023.

“I like being different than everyone,” she said. “Some people think that it’s weird that I can fly planes but I can’t drive a car – I mean, I can, but a lot of people think it’s funny.”

A spokesperson for East Coast Jets, where pilot Jeff Gregory used to work, said: “We are deeply saddened to learn that Capt Jeff Gregory was among those who lost their lives in yesterday’s tragic aviation accident in Palm Beach.”

He was married with two children, US media report.